Legal experts say the president is flouting the spirt of vacancies statute.

President Trump on Monday circumvented the typical temporary appointment process by naming an individual with no existing role in the federal government to be the acting head of an agency.

Ken Cuccinelli, the former attorney general of Virginia, will serve as acting chief of U.S. Citizenship and Immigration Services. He joins a long list of top officials at the Homeland Security Department serving in a temporary capacity, including acting Secretary Kevin McAleenan.

USCIS said Trump appointed Cuccinelli to the role under the 1998 Federal Vacancies Reform Act, but did not elaborate on the specific legal avenue the administration followed. The law requires that acting officials for Senate-confirmed positions come either from the first assistant to that position or elsewhere in the executive branch. In the latter category, employees must be either in a GS-15 position or above for at least 90 days prior to the vacancy or in a separate Senate-confirmed role.

Cuccinelli came to USCIS from the private sector, working most recently as a CNN contributor. To circumvent the Vacancies Reform Act requirements, Cuccinelli will officially serve in a newly created principal deputy director position that will make him first assistant and thus next in line for acting director. An agency official said the acting director requires no confirmation and Cuccinelli’s appointment is in compliance with the vacancies law.

“It is up to the president to nominate, or not, for a permanent appointment and that would require Senate confirmation,” the official said.

The Trump administration's strategy could still leave the selection on rocky legal footing. The Justice Department’s Office of Legal Counsel ruled in 1998 an individual named to a first assistant position after a new vacancy opened up could not serve in an acting capacity. It reversed course in 2001, but the ruling has never faced a legal challenge.

Anne Joseph O’Connell, a professor at Stanford Law School who is writing a book on temporary leaders in government, said there is also legal uncertainty over whether agencies can simply create new first assistant positions, noting those roles are typically spelled out in statute or regulations. Both legal issues, O’Connell said, “suggest an undermining of the spirit of” the vacancies law.

Rebecca Jones, policy counsel at the Project on Government Oversight, said the administration’s approach was “very suspect” and in contrast to the vacancies law's design.

“It’s very much skirting with unconstitutionality,” said Jones, who called on Congress to address both the immediate issue with Cuccinelli and the larger loopholes in the vacancies law.

The Government Accountability Office is tasked with enforcing the Vacancies Reform Act, but has typically only weighed in when acting leaders serve longer than statutorily allowed.

O’Connell said it was unusual for a president to rely so heavily on the vacancies act when the Senate is controlled by the same party as the White House.

“This action is not about gap filling when you need to fill gaps but is really about an end run around Senate confirmation” and the vacancies law, O’Connell said.

Trump may have chosen the temporary appointment path rather than a permanent one precisely for that reason. Cuccinelli has made political enemies in both parties and would face slim chances of confirmation if he came up for a vote before the Senate. Majority Leader Mitch McConnell, R-Ky., for example, has voiced opposition to Cuccinelli receiving an administration post. Trump has frequently pushed the boundaries of succession and appointments under the vacancies law.

Rep. Bennie Thompson, D-Miss., who chairs the House Homeland Security Committee, announced his opposition Cuccinelli's appointment as well, calling him "completely unqualified."

"With both Democrats and Republicans opposing him, there is no reason for President Trump to install someone who has no chance of Senate confirmation,” Thompson said.

For his part, Cuccinelli said he was excited to “serve alongside this agency’s dedicated workforce.”

“I look forward to working with the men and women of USCIS to ensure our legal immigration system operates effectively and efficiently while deterring fraud and protecting the American people,” the acting leader said.